GDU, a novel signalling protein

ABSTRACT

The present invention provides the nucleotide and amino acid sequence of a previously unidentified erbB receptor target.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on PCT Application No. PCT/AU96/00258, filed May 2, 1996; which is a continuation of Australian Patent Application No. PN 2742, filed May 2, 1995.

The present invention relates to a previously unidentified erbB receptor target designated GDU. The present invention relates to a polynucleotide encoding GDU and to methods of detecting the presence of GDU.

Many intracellular targets for receptor tyrosine kinases (RTKs) contain one or more src homology (SH)2 domains. These are conserved, non-catalytic domains of approximately 100 amino acids which bind to short peptide sequences containing phosphotyrosine (Cohen et al, Cell 80, 237-248, 1995). Since receptor autophosphorylation on specific tyrosine residues follows RTK activation, SH2 domains mediate receptor-substrate, as well as other protein-protein interactions, during signal transduction. SH2 domains contain not only a pocket lined with basic residues which binds the phosphotyrosine but also an additional binding pocket or groove which interacts with amino acids C-terminal to this residue, this determining the specificity of the interaction. The particular autophosphorylation sites present on a given RTK therefore define the SH2 domain-containing signalling proteins that it can recruit and hence, to a large extent, the signalling specificity of the receptor. SH2 domains are often accompanied in signalling proteins by two other conserved protein modules; SH3 domains, which bind to proline-rich peptide ligands, and pleckstrin-homology (PH) domains. The function of the latter remains ill-defined, and both protein and phospholipid ligands have been described.

SH2 domain-containing proteins can be divided into two classes (Schlessinger and Ullrich Neuron, 9,383-301 1992); Class I, which also possess a catalytic function e.g. phospholipase C-γ1 (PLC-γ1) and the GTPase activating protein for Ras (Ras-GAP), and Class II, which contain only non-catalytic protein modules and are thought to function as adaptors, linking separate catalytic subunits to receptors or other signalling proteins e.g. Grb2. The tissue expression of particular SH2 domain-containing proteins varies from ubiquitous, e.g. Grb2, which performs a fundamental role in linking tyrosine kinases to Ras signalling, to relatively restricted e.g. Grb7, which is mainly expressed in the liver and kidney (Margolis et al Proc. Natl. Acad.

Sci. USA, 89, 8894-8898, 1992). Presumably the latter protein performs relatively specialised signalling functions. The CORT (cloning of receptor targets) technique, in which cDNA expressionlibranes are screened with the tyrosine phosphorylated C-terminus of the EGF receptor represents a powerful methodology for the identification and characterisation of novel, SH2 domain-containing, receptor substrates (Skolnik et al Cell 65, 83-90, 1991).

Members of the erbB family of RTKs and their ligands are implicated both in normal mammary gland development and the growth and progression of human breast cancer. Furthermore, marked alterations in the expression or activity of several SH2 domain-containing proteins have been observed in human breast cancers or breast cancer-derived cell lines, suggesting that this represents an additional level at which RTK signalling may be modulated in this disease (Daly, Breast Cancer Res Treat, 34, 85-92, 1995). We therefore chose normal human mammary epithelial cells as a basis for a CORT screening program and hence identification of novel, and relatively tissue specific, erbB receptor targets.

Screening of a HMEC 184 λEXlox cDNA library isolated 1 Ras-GAP, 2 Grb2 cDNAs and a cDNA encoding a novel SH2 domain-containing protein. This protein, designated GDU or Grb14 (the designations “GDU” and “Grb14” are used interchangeably herein), is related both in molecular architecture and sequence homology to Grb7 and Grb10, previously identified erbB receptor targets. These three proteins also share significant sequence homology, over an approximately 300 amino acid region encompassing the PH domain, with the C. elegans gene F10E9.6. The latter gene has recently been shown to encode a protein (mig. 10) critical for longitudinal neuronal migration in C. elegans; members of the Grb7 gene family, including GDU, may therefore be involved in the regulation of cell migration in higher organisms.

Analysis of GDU gene expression in normal breast epithelial cells and a large series of human breast cancer cell lines revealed that expression was limited predominantly to normal breast cells and the more highly differentiated, estrogen receptor positive, breast cancer cell lines. Also, GDU mRNA was overexpressed in the DU-145 prostate carcinoma cell line relative to the normal prostate and two other prostate cancer cell lines. GDU may therefore serve as a prognostic indicator and/or a tumour marker in both breast and prostate cancer. Furthermore, since altered expression of GDU may contribute to the abnormal proliferation, invasion and/or migration of cancer cells, GDU signal transduction may provide a novel therapeutic target in human cancer. Finally, since GDU is involved in downstream signalling initiated by the platelet derived growth factor receptor (PDGFR), it may provide a target in diseases or conditions in which PDGF plays a regulatory role e.g. wound healing, fibrotic conditions, atherosclerosis.

In a first aspect the present invention consists in a polynucleotide encoding GDU, the polynucleotide having a sequence which encodes a polypeptide having an amino acid sequence as shown in FIG. 2 or a sequence which hybridises thereto.

In a preferred embodiment of the present invention the polynucleotide has a sequence as shown in FIG. 2.

In a second aspect the present invention consists in a polypeptide, the polypeptide having an amino acid sequence as shown in FIG. 2.

In a third aspect the present invention consists in an antibody which binds to the polypeptide of the second aspect of the present invention.

The antibody may be monoclonal or polyclonal, however, it is presently preferred that the antibody is a monoclonal antibody.

In a fourth aspect, the present invention consists in an oligonucleotide probe of at least 12 nucleotides, the oligonucleotide probe having a sequence such that the probe selectively hybridises to the polynucleotide of the first aspect of the present invention under stringent conditions.

In a preferred embodiment of this aspect of the present invention the oligonucleotide is labelled. In a further preferred embodiment of the present invention the oligonucleotide is of at least 18 nucleotides.

In a fifth aspect the present invention consists in method of detecting the presence of GDU in a sample, the method comprising reacting the sample with an antibody of the second aspect of the present invention or a oligonucleotide probe of the fourth aspect of the present invention and detecting the binding of the antibody or the probe.

In order that the nature of the present invention may be more clearly understood preferred forms thereof will now be described with reference to the following examples and Figures in which:

FIG. 1 shows a schematic representation of Grb14 structure with a restriction map for the Grb14 cDNA and the cDNA clones used to derive the Grb14 sequence aligned underneath. The initial clone isolated by CORT screening was designated clone 1. Two other clones (1-1 and 1-2) were isolated from the 184 cell line library by screening using clone 1 as a probe. The Grb14 cDNA sequence was completed using two clones L5 and L6, isolated from a human liver cDNA library. Abbreviations are as follows: A; Apa I; Av; Avr II, X; Xho I; E; Eco RI. The numbers refer to distance in bp.

FIG. 2 shows the nucleotide and amino acid sequence of Grb14. The PH domain is underlined and the SH2 domain indicated by bold type. The translation termination codon is shown by an asterisk in the amino acid sequence. Numbers refer to distances in bp.

FIG. 3 shows the sequence homology between Grb14, (SEQ ID:2), Grb7, (SEQ ID:3), Grb10 (SEQ ID:4), and F10E9.6. As alignment of the amino acid sequences of Grb14, mouse Grb7, mouse Grb10 and C. elegans F10E9.6 was obtained using the computer programs Clustal W and SeqVu. Identical residues are boxed. A highly conserved proline-rich motif is indicated by the dotted underline, the PH domain by the broken underline and the SH2 domain by the bold underline. Only the central region of F10E9.6 exhibiting homology with the Grb7 family is shown. Amino acid residues for each protein are numbered (from the initiation methionine) on the right.

SCREENING OF A NORMAL BREAST EPITHELIAL CELL CDNA LIBRARY BY THE CORT TECHNIQUE

CORT screening of two cDNA libraries prepared from normal breast epithelial cells led to the isolation of recombinants which exhibited differential binding to the phosphorylated EGFR C-terminus. Upon excision of the corresponding pEXIox plasmids and sequencing of the DNA inserts, two recombinants which bound very strongly were identified as Grb2 cDNA clones (Lowenstein et al 1992, Cell 70, 431-442, 1992), and a clone exhibiting moderate binding corresponded to ras-GAP (Trahey et al. Science 242, 1696-1700, 1988). The final clone, designated GDU, bound only weakly to the EGFR. A database search with the corresponding cDNA sequence did not detect an exact match but revealed significant sequence homology with the SH2 domain-containing protein Grb7 (Margolis et al PNAS 89, 8894-8898, 1992). The cDNA (GDU Clone 1 in FIG. 1) encoded a short stretch of amino acids followed by a C-terminal SH2 domain; homology to Grb7 was apparent over this entire open reading frame.

Characterisation of GDU

In order to obtain the full length cDNA sequence for GDU, two cDNA library screens were performed. In the first, the cDNA insert from Clone 1 was used to screen the breast cDNA library. Screening of 5×10⁵ recombinants isolated 2 cDNAs, designated 1-1 and 1-2, of 1.6 and 1.4 kb, respectively (FIG. 1). In the second, a 213bp EcoRI-Xho I restriction fragment derived from 1-1 (FIG. 1) was used to screen a human liver cDNA library. Screening of 1×10⁶ recombinants isolated 2 cDNAs, designated L5 and L6, of 1.3 and 1.7 kb, respectively (FIG. 1). Clones 1-1, 1-2, L5 and L6 were sequenced in their entirety on both strands to obtain the cDNA sequence shown in FIG. 2. The 2.4 kb of DNA sequence derived from these overlapping clones corresponds closely to the size of the three most abundant mRNA species detected upon Northern blot analysis.

Analysis of the cDNA sequence identified an open reading frame of 540 amino acids. The initiation codon is preceded by an in-frame termination codon and is surrounded by a consensus sequence for strong translational initiation. The encoded protein is similar both in molecular architecture and amino acid sequence to Grb7 (Margolis et al, Proc. Natl. Acad. Sci. USA 89, 8894-8898, 1992) and the recently identified Grb10 (Ooi et al, Oncogene 10, 1621-1630, 1995), consisting of a N-terminal region containing at least one proline-rich motif, a central region which exhibits significant homology to the putative C. elegans protein F10E9.6 (Stein et al EMBO J, 13, 1331-1340, 1994) and which also encompasses a PH domain, and a C-terminal SH2 domain. An alignment of the amino acid sequences of GDU, Grb7, Grb10 and F10E9.6 is shown in FIG. 3.

GDU is similar in size to Grb7, Grb10 possessing a more extended N-terminus. The N-terminal region exhibits low sequence homology between GDU, Grb7 and Grb10 apart from a highly conserved amino acid motif PS/AIPNPFPEL. Also of note is the presence of two clusters of basic residues which flank this motif. Overall the N-terminal region of GDU displays a lower proline content than that of Grb7 and Grb10 (GDU amino acids 1-110; 11% proline, Grb10 amino acids 1-113; 15%, Grb7 amino acids 1-103; 23%).

GDU, Grb7 and Grb10 share a central, conserved region of approximately 320 amino acids which exhibits significant homology to a domain found in the C. elegans protein F10E9.6. Over this region, GDU bears 48, 55 and 28% amino acid identify respectively with Grb7, Grb10 and F10E9.6 (FIG. 3). The core of this region is provided by a PH domain (FIGS. 1, 2 and 3), over which GDU exhibits 56, 61 and 35% amino acid identity, respectively, with Grb7, Grb10 and F10E9.6. However, as noted by Ooi et al, (Oncogene 10, 1621-1630, 1995) another region of particularly marked homology spanning approximately 100 amino acids exists amino-terminal to the PH domain (FIG. 3).

The most highly conserved region amongst Grb7 family members is the SH2 domain (FIG. 3). The GDU SH2 domain displays 67 and 74% amino acid identity, respectively, with the corresponding domain in Grb7 and Grb10.

Northern Blot Analysis of GDU Gene Expression

The tissue specificity of GDU gene expression was investigated by hybridizing Northern blots of poly A+ RNA isolated from a variety of human tissues to a GDU specific cDNA probe. GDU gene expression was highest in the testis, ovary, heart, liver, skeletal muscle, kidney and pancreas. Moderate expression was detected in the small intestine, colon, peripheral blood leukocytes, brain and placenta, whilst expression in the spleen, thymus, prostate and lung was low or undetectable. Several mRNA transcripts were detected which displayed tissue-specific variation in their relative abundance. The three most prominent transcripts were approximately 2.3, 2.4 and 2.5 kb. Often co-expressed with one or two of these transcripts was a transcript of approximately 9.5 kb. In the ovary a still larger transcript of undetermined size was also expressed.

Since the Grb14 cDNA was originally isolated from a cDNA library prepared from normal human breast epithelial cells, we were interested in determining the expression profile of Grb14 mRNA in a panel of human breast cancer cell lines. Upon Northern blot analysis of total RNA isolated from 3 normal human breast epithelial cell strains and 19 human breast cancer cell lines, Grb14 gene expression could be detected in HMEC 184 and HMEC-219-4 cells, 6/7 ER+human breast cancer cell lines and 2/12 ER-cell lines (Table 1). Thus Grb14 gene expression appears largely restricted to normal breast epithelial and ER+breast cancer cells. Differential expression of Grb14 was also observed amongst human prostate cancer cell lines. Although Grb14 MRNA expression was undetectable in the normal prostate, low expression could be detected in the PC3 and LnGaP prostate cancer cell lines and high expression in the DU145 line (Table 1).

Origin Cell Line Expression Normal human breast epithelial HMEC 184 +++ HMEC-219-4 + HMEC-1001-7 − Human breast cancer, ER + T-47D +++ ZR-75-1 ++ MCF-7 + BT-483 + MDA-MB-134 + MDA-MB-361 + BT-474 − Human breast cancer, ER− MDA-MB-330 + MDA-MB-468 + BT-20 − SK-BR-3 − BT-549 − H3578T − DU-4475 − MDA-MB-157 − MDA-MB-175 − MDA-MB-231 − MDA-MB-436 − MDA-MB-453 − Human prostate cancer PC3 + LnCaP + DU-145 ++++ Human epidermoid carcinoma A431 − Human embryonic kidney HEK 293 ++++

Table 1. Expression of Grb14 mRNA in different human cell lines. Total cellular RNA was extracted from the indicated cell lines and subjected to Northern blot analysis using a Grb14 cDNA probe. The relative expression levels of Grb14 mRNA were then scored on a scale from +(low) to ++++(high). −; undetectable expression.

Expression of Grb14 Protein

In order to characterize the Grb14 protein a polyclonal antiserum was raised against a GST-Grb14 SH2 domain fusion protein. Following affinity purification, this antiserum was used to Western blot cell lysates derived from cell lines in which Grb14 mRNA was either expressed at high levels (DU145 and HEK 293) or was undetectable (A431 and SK-BR-3) (Table 1). The antiserum recognized a protein of approximately 58 kDa in DU145 cells, whilst in HEK 293 cells a tight doublet of this mobility was detected. These bands were not observed upon Western blotting with pre-immune serum or in the cell lines which do not express Grb14 mRNA. This estimated size of Grb14 upon SDS-PAGE is in accordance with the predicted size of the translation product of the Grb14 cDNA (60 kDa).

Since DU145 cells overexpress Grb14 mRNA relative to the two other prostate carcinoma cell lines examined (Table 1), we investigated whether this was accompanied by an upregulation of Grb14 protein expression. Upon Western blot analysis, Grb14 was clearly detectable in DU145, but not PC3 or LnCaP, cell lysates, indicating that Grb14 protein is overexpressed in this cell line.

Phosphorylation of Grb14

In order to characterize further the role of Grb14 in receptor tyrosine kinase signalling, the phosphorylation state of Grb14 was investigated before and after growth factor stimulation. Since the anti-Grb14 antiserum 264 did not immunoprecipitate Grb14 under either native or denaturing conditions, we utilized an expression construct (pRcCMV_(Flag)) which tagged Grb14 with the 8 amino acid Flag epitope at the C-terminus. This construct was stably transfected into HEK 293 cells, leading to the isolation of stable clones of cells expressing an epitope-tagged Grb14 which could be immunoprecipitated with the M2 anti-Flag monoclonal antibody and Western blotted with either this antibody or anti-Grb14 antiserum 264. Immunoprecipitation of Grb14 from serum starved cells which were metabolically labelled with ³²P-orthophosphate demonstrated that Grb14 was phosphorylated in this basal state. Phosphoamino acid analysis of the isolated protein demonstrated that phosphorylation was on serine residues.

Treatment of the cells with EGF did not significantly increase this level of phosphorylation, although activation of native EGFRs could be demonstrated by anti-phosphotyrosine blotting of the cell lysates. However, stimulation with PGDF BB resulted in an approximately 1.5 fold increase within 5 min of administration, and transient transfection of a cDNA encoding β-PDGFRs into the cells further amplified this response to approximately 2-fold. The small increase in phosphorylation which occurred when this construct was present in the absence of PGDF BB was presumably due to the constitutive activation of RTKs often observed with this system. Phosphoamino acid analysis demonstrated that the PDGF-induced increases in Grb14 phosphorylation also occurred on serine residues.

As will be recognised by persons skilled in this field the present inventors have identified a novel signalling molecule which they pave designated GDU or Grb14. GDU has the potential to be used as a prognostic indicator/tumour marker in both breast and prostate cancer. In addition, as GDU may influence invasive/ metastatic behaviour it may also serve as a marker of invasive/metastatic disease in these and other cancers. Finally, the involvement of GDU in signalling by the PDGFR suggests that it may represent a therapeutic target in diseases or conditions in which PDGF plays a regulatory role.

Signalling via GDU could be targeted by competitive peptides or dominant negative mutants, or restored by gene therapy. The information provided herein will clearly assist in the rational design of a GDU antagonist.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. 

What is claimed is:                    #             SEQUENCE LISTING <160> NUMBER OF SEQ ID NOS: 5 <210> SEQ ID NO 1 <211> LENGTH: 2404 <212> TYPE: DNA <213> ORGANISM: Homo sapiens <400> SEQUENCE: 1 cggatgaggg tcagggctgc gcggacccct atcccgcctg cgtcctcccg g #caagcccag     60 cgggagcgcc cgctcggctg ggtccccgcc tccagcgcgc cggggccgcc c #agaccctgg    120 gctcagcctc gcgccccggt gcccacctga ggaggcggcg gtcccggcct c #gcgtcccgg    180 atgggacggc gcgggagcaa tgccagtggc cccgagcgcc ccgggccacg c #gcggggccg    240 gccagccgct ctcgcgccct ccccgccccc tccgcgcctt gcctcgccgc c #cgcgcgccc    300 cacccaccgg ccgctcctcc cctctcccca ccctcctcct ccgccccctc c #cctcccccg    360 ccgcctcgca gatagctcgg ccgcgcgtct cagccgccgg ggccccgagc g #caggcggcg    420 aggccaccac acctgcagag cgctcgggct gcctaggcgg cacctcgcct c #ccgccgcgc    480 aaaccccttc tccccacgcg ccgagtctcc catgacgccc gagccccccg g #ccggcgaca    540 atgaccactt ccctgcaaga tgggcagagc gccgcgagca gggcggctgc c #cgggattcg    600 ccgctggccg cccaggtgtg tggcgctgcc caggggaggg gcgacgccca c #gacctggcg    660 ccggccccct ggctgcacgc gcgagcgctc ctgccccttc cggacgggac c #cgcggctgt    720 gctgcagaca ggagaaaaaa gaaagatctt gatgttccgg aaatgccatc t #attccaaac    780 ccttttcctg agctatgctg ttctccaatt acatctgtgt tgtcagcaga c #ctatttccc    840 aaagcaaatt caaggaaaaa acaggtgatt aaagtataca gtgaagatga a #accagcagg    900 gctttagatg tacccagtga cataacggct cgagatgttt gtcagctgtt g #atcctgaag    960 aatcattaca ttgatgacca cagctggacc ctttttgagc acctgcctca c #ataggtgta   1020 gaaagaacaa tagaagacca cgaactggtg attgaagtgc tatccaactg g #gggatagaa   1080 gaagaaaaca aactatactt tagaaaaaat tatgccaaat atgagttctt t #aaaaaccca   1140 atgtattttt ttccagagca tatggtatct tttgcaactg aaaccaatgg t #gaaatatcc   1200 cccacacaga ttttgcagat gtttctgagt tcaagcacat atcctgaaat t #catggtttc   1260 ttacatgcga aagaacaggg aaagaagtct tggaaaaaaa tttacttttt t #ctaagaaga   1320 tctggtttat atttttctac taaaggaaca tcaaaggaac cgcggcattt g #cagtttttc   1380 agcgaatttg gcaatagtga tatttatgtg tcactggcag gcaaaaaaaa a #catggagca   1440 ccgactaact atggattctg ctttaagcct aacaaagcgg gagggccccg a #gacctgaaa   1500 atgctctgtg cagaagaaga gcagagtagg acgtgctggg tgaccgcgat t #agattgctt   1560 aagtatggca tgcagctgta ccagaattat atgcatccat atcaaggtag a #agtggctgc   1620 agttcacaga gcatatcacc tatgagaagt atatcagaga attccctggt a #gcaatggac   1680 ttctcaggcc agaaaagcag agttatagaa aatcccactg aagccctttc a #gttgcggtt   1740 gaagaaggac tcgcttggag gaaaaaagga tgtttacgcc tgggcactca c #ggtagcccc   1800 actgcctctt cacagagctc tgccacaaac atggctatcc accggtccca g #ccatggttt   1860 caccacaaaa tttctagaga tgaggctcag cgattgatta ttcagcaagg a #cttgtggat   1920 ggagttttct tggtacggga tagtcagagt aaccccaaaa ctttcgtact g #tcaatgagt   1980 catggacaaa aaataaagca ctttcaaatt ataccagtag aagatgacgg t #gaaatgttc   2040 cacacactgg atgatggcca cacaagattt acagatctaa tacagctggt g #gagttctat   2100 caactcaata agggcgttct tccttgcaag ttgaaacatt attgtgctag g #attgctctc   2160 tagacaagcc agaagtgact tattaaacta ttgaaggaaa aggactcaag a #aaaataata   2220 aaagaccata aataagggcg aaaacattat catgtgaaaa gaatgtattt c #acctgcaag   2280 ttacaaaaaa atagtttgtg cattgcaaat aagcaaagac ttggattgac t #ttacattca   2340 tcatttaaaa ttcattagtt aaaattaaac cttaggaaaa aaaaaaaaaa a #aaaaaaaaa   2400 aaaa                  #                   #                   #           2404 <210> SEQ ID NO 2 <211> LENGTH: 540 <212> TYPE: PRT <213> ORGANISM: Homo sapiens <400> SEQUENCE: 2 Met Thr Thr Ser Leu Gln Asp Gly Gln Ser A #la Ala Ser Arg Ala Ala   1               5  #                 10  #                 15 Ala Arg Asp Ser Pro Leu Ala Ala Gln Val C #ys Gly Ala Ala Gln Gly              20      #             25      #             30 Arg Gly Asp Ala His Asp Leu Ala Pro Ala P #ro Trp Leu His Ala Arg          35          #         40          #         45 Ala Leu Leu Pro Leu Pro Asp Gly Thr Arg G #ly Cys Ala Ala Asp Arg      50              #     55              #     60 Arg Lys Lys Lys Asp Leu Asp Val Pro Glu M #et Pro Ser Ile Pro Asn  65                  # 70                  # 75                  # 80 Pro Phe Pro Glu Leu Cys Cys Ser Pro Ile T #hr Ser Val Leu Ser Ala                  85  #                 90  #                 95 Asp Leu Phe Pro Lys Ala Asn Ser Arg Lys L #ys Gln Val Ile Lys Val             100      #            105      #            110 Tyr Ser Glu Asp Glu Thr Ser Arg Ala Leu A #sp Val Pro Ser Asp Ile         115          #        120          #        125 Thr Ala Arg Asp Val Cys Gln Leu Leu Ile L #eu Lys Asn His Tyr Ile     130              #    135              #    140 Asp Asp His Ser Trp Thr Leu Phe Glu His L #eu Pro His Ile Gly Val 145                  #150                  #155                  #160 Glu Arg Thr Ile Glu Asp His Glu Leu Val I #le Glu Val Leu Ser Asn                 165  #                170  #                175 Trp Gly Ile Glu Glu Glu Asn Lys Leu Tyr P #he Arg Lys Asn Tyr Ala             180      #            185      #            190 Lys Tyr Glu Phe Phe Lys Asn Pro Met Tyr P #he Phe Pro Glu His Met         195          #        200          #        205 Val Ser Phe Ala Thr Glu Thr Asn Gly Glu I #le Ser Pro Thr Gln Ile     210              #    215              #    220 Leu Gln Met Phe Leu Ser Ser Ser Thr Tyr P #ro Glu Ile His Gly Phe 225                  #230                  #235                  #240 Leu His Ala Lys Glu Gln Gly Lys Lys Ser T #rp Lys Lys Ile Tyr Phe                 245  #                250  #                255 Phe Leu Arg Arg Ser Gly Leu Tyr Phe Ser T #hr Lys Gly Thr Ser Lys             260      #            265      #            270 Glu Pro Arg His Leu Gln Phe Phe Ser Glu P #he Gly Asn Ser Asp Ile         275          #        280          #        285 Tyr Val Ser Leu Ala Gly Lys Lys Lys His G #ly Ala Pro Thr Asn Tyr     290              #    295              #    300 Gly Phe Cys Phe Lys Pro Asn Lys Ala Gly G #ly Pro Arg Asp Leu Lys 305                  #310                  #315                  #320 Met Leu Cys Ala Glu Glu Glu Gln Ser Arg T #hr Cys Trp Val Thr Ala                 325  #                330  #                335 Ile Arg Leu Leu Lys Tyr Gly Met Gln Leu T #yr Gln Asn Tyr Met His             340      #            345      #            350 Pro Tyr Gln Gly Arg Ser Gly Cys Ser Ser G #ln Ser Ile Ser Pro Met         355          #        360          #        365 Arg Ser Ile Ser Glu Asn Ser Leu Val Ala M #et Asp Phe Ser Gly Gln     370              #    375              #    380 Lys Ser Arg Val Ile Glu Asn Pro Thr Glu A #la Leu Ser Val Ala Val 385                  #390                  #395                  #400 Glu Glu Gly Leu Ala Trp Arg Lys Lys Gly C #ys Leu Arg Leu Gly Thr                 405  #                410  #                415 His Gly Ser Pro Thr Ala Ser Ser Gln Ser S #er Ala Thr Asn Met Ala             420      #            425      #            430 Ile His Arg Ser Gln Pro Trp Phe His His L #ys Ile Ser Arg Asp Glu         435          #        440          #        445 Ala Gln Arg Leu Ile Ile Gln Gln Gly Leu V #al Asp Gly Val Phe Leu     450              #    455              #    460 Val Arg Asp Ser Gln Ser Asn Pro Lys Thr P #he Val Leu Ser Met Ser 465                  #470                  #475                  #480 His Gly Gln Lys Ile Lys His Phe Gln Ile I #le Pro Val Glu Asp Asp                 485  #                490  #                495 Gly Glu Met Phe His Thr Leu Asp Asp Gly H #is Thr Arg Phe Thr Asp             500      #            505      #            510 Leu Ile Gln Leu Val Glu Phe Tyr Gln Leu A #sn Lys Gly Val Leu Pro         515          #        520          #        525 Cys Lys Leu Lys His Tyr Cys Ala Arg Ile A #la Leu     530              #    535              #    540 <210> SEQ ID NO 3 <211> LENGTH: 535 <212> TYPE: PRT <213> ORGANISM: Mus musculus <400> SEQUENCE: 3 Met Glu Leu Asp Leu Ser Pro Thr His Leu S #er Ser Ser Pro Glu Asp   1               5  #                 10  #                 15 Val Cys Pro Thr Pro Ala Thr Pro Pro Glu T #hr Pro Pro Pro Pro Asp              20      #             25      #             30 Asn Pro Pro Pro Gly Asp Val Lys Arg Ser G #ln Pro Leu Pro Ile Pro          35          #         40          #         45 Ser Ser Arg Lys Leu Arg Glu Glu Glu Phe G #ln Ala Thr Ser Leu Pro      50              #     55              #     60 Ser Ile Pro Asn Pro Phe Pro Glu Leu Cys S #er Pro Pro Ser Gln Lys  65                  # 70                  # 75                  # 80 Pro Ile Leu Gly Gly Ser Ser Gly Ala Arg G #ly Leu Leu Pro Arg Asp                  85  #                 90  #                 95 Ser Ser Arg Leu Cys Val Val Lys Val Tyr S #er Glu Asp Gly Ala Cys             100      #            105      #            110 Arg Ser Val Glu Val Ala Ala Gly Ala Thr A #la Arg His Val Cys Glu         115          #        120          #        125 Met Leu Val Gln Arg Ala His Ala Leu Ser A #sp Glu Ser Trp Gly Leu     130              #    135              #    140 Val Glu Ser His Pro Tyr Leu Ala Leu Glu A #rg Gly Leu Glu Asp His 145                  #150                  #155                  #160 Glu Phe Val Val Glu Val Gln Glu Ala Trp P #ro Val Gly Gly Asp Ser                 165  #                170  #                175 Arg Phe Ile Phe Arg Lys Asn Phe Ala Lys T #yr Glu Leu Phe Lys Ser             180      #            185      #            190 Pro Pro His Thr Leu Phe Pro Glu Lys Met V #al Ser Ser Cys Leu Asp         195          #        200          #        205 Ala Gln Thr Gly Ile Ser His Glu Asp Leu I #le Gln Asn Phe Leu Asn     210              #    215              #    220 Ala Gly Ser Phe Pro Glu Ile Gln Gly Phe L #eu Gln Leu Arg Gly Ser 225                  #230                  #235                  #240 Gly Arg Gly Ser Gly Arg Lys Leu Trp Lys A #rg Phe Phe Cys Phe Leu                 245  #                250  #                255 Arg Arg Ser Gly Leu Tyr Tyr Ser Thr Lys G #ly Thr Ser Lys Asp Pro             260      #            265      #            270 Arg His Leu Gln Tyr Val Ala Asp Val Asn G #lu Ser Asn Val Tyr Val         275          #        280          #        285 Val Thr Gln Gly Arg Lys Leu Tyr Gly Met P #ro Thr Asp Phe Gly Phe     290              #    295              #    300 Cys Val Lys Pro Asn Lys Leu Arg Asn Gly H #is Lys Gly Leu His Ile 305                  #310                  #315                  #320 Phe Cys Ser Glu Asp Glu Gln Ser Arg Thr C #ys Trp Leu Ala Ala Phe                 325  #                330  #                335 Arg Leu Phe Lys Tyr Gly Val Gln Leu Tyr L #ys Asn Tyr Gln Gln Ala             340      #            345      #            350 Gln Ser Arg His Leu Arg Leu Ser Tyr Leu G #ly Ser Pro Pro Leu Arg         355          #        360          #        365 Ser Val Ser Asp Asn Thr Leu Val Ala Met A #sp Phe Ser Gly His Ala     370              #    375              #    380 Gly Arg Val Ile Asp Asn Pro Arg Glu Ala L #eu Ser Ala Ala Met Glu 385                  #390                  #395                  #400 Glu Ala Gln Ala Trp Arg Lys Lys Thr Asn H #is Arg Leu Ser Leu Pro                 405  #                410  #                415 Thr Thr Cys Ser Gly Ser Ser Leu Ser Ala A #la Ile His Arg Thr Gln             420      #            425      #            430 Pro Trp Phe His Gly Arg Ile Ser Arg Glu G #lu Ser Gln Arg Leu Ile         435          #        440          #        445 Gly Gln Gln Gly Leu Val Asp Gly Val Phe L #eu Val Arg Glu Ser Gln     450              #    455              #    460 Arg Asn Pro Gln Gly Phe Val Leu Ser Leu C #ys His Leu Gln Lys Val 465                  #470                  #475                  #480 Lys His Tyr Leu Ile Leu Pro Ser Glu Asp G #lu Gly Cys Leu Tyr Phe                 485  #                490  #                495 Ser Met Asp Glu Gly Gln Thr Arg Phe Thr A #sp Leu Leu Gln Leu Val             500      #            505      #            510 Glu Phe His Gln Leu Asn Arg Gly Ile Leu P #ro Cys Leu Leu Arg His         515          #        520          #        525 Cys Cys Ala Arg Val Ala Leu     530              #    535 <210> SEQ ID NO 4 <211> LENGTH: 621 <212> TYPE: PRT <213> ORGANISM: Mus musculus <400> SEQUENCE: 4 Met Asn Asn Asp Ile Asn Ser Ser Val Glu S #er Leu Asn Ser Ala Cys   1               5  #                 10  #                 15 Asn Met Gln Ser Asp Thr Asp Thr Ala Pro L #eu Leu Glu Asp Gly Gln              20      #             25      #             30 His Ala Ser Asn Gln Gly Ala Ala Ser Ser S #er Arg Gly Gln Pro Gln          35          #         40          #         45 Ala Ser Pro Arg Gln Lys Met Gln Arg Ser G #ln Pro Val His Ile Leu      50              #     55              #     60 Arg Arg Leu Gln Glu Glu Asp Gln Gln Leu A #rg Thr Ala Ser Leu Pro  65                  # 70                  # 75                  # 80 Ala Ile Pro Asn Pro Phe Pro Glu Leu Thr G #ly Ala Ala Pro Gly Ser                  85  #                 90  #                 95 Pro Pro Ser Val Ala Pro Ser Ser Leu Pro P #ro Pro Pro Ser Gln Pro             100      #            105      #            110 Pro Ala Lys His Cys Gly Arg Cys Glu Lys T #rp Ile Pro Gly Glu Asn         115          #        120          #        125 Thr Arg Gly Asn Gly Lys Arg Lys Ile Trp A #rg Trp Gln Phe Pro Pro     130              #    135              #    140 Gly Phe Gln Leu Ser Lys Leu Thr Arg Pro G #ly Leu Trp Thr Lys Thr 145                  #150                  #155                  #160 Thr Ala Arg Phe Ser Lys Lys Gln Pro Lys A #sn Gln Cys Pro Thr Asp                 165  #                170  #                175 Thr Val Asn Pro Val Ala Arg Met Pro Thr S #er Gln Met Glu Lys Leu             180      #            185      #            190 Arg Leu Arg Lys Asp Val Lys Val Phe Ser G #lu Asp Gly Thr Ser Lys         195          #        200          #        205 Val Val Glu Ile Leu Thr Asp Met Thr Ala A #rg Asp Leu Cys Gln Leu     210              #    215              #    220 Leu Val Tyr Lys Ser His Cys Val Asp Asp A #sn Ser Trp Thr Leu Val 225                  #230                  #235                  #240 Glu His His Pro Gln Leu Gly Leu Glu Arg C #ys Leu Glu Asp His Glu                 245  #                250  #                255 Ile Val Val Gln Val Glu Ser Thr Met Pro S #er Glu Ser Lys Phe Leu             260      #            265      #            270 Phe Arg Lys Asn Tyr Ala Lys Tyr Glu Phe P #he Lys Asn Pro Val Asn         275          #        280          #        285 Phe Phe Pro Asp Gln Met Val Asn Trp Cys G #ln Gln Ser Asn Gly Gly     290              #    295              #    300 Gln Ala Gln Leu Leu Gln Asn Phe Leu Asn T #hr Ser Ser Cys Pro Glu 305                  #310                  #315                  #320 Ile Gln Gly Phe Leu Gln Val Lys Glu Val G #ly Arg Lys Ser Trp Lys                 325  #                330  #                335 Lys Leu Tyr Val Cys Leu Arg Arg Ser Gly L #eu Tyr Tyr Ser Thr Lys             340      #            345      #            350 Gly Thr Ser Lys Glu Pro Arg His Leu Gln L #eu Leu Ala Asp Leu Glu         355          #        360          #        365 Glu Ser Ser Ile Phe Tyr Leu Ile Ala Gly L #ys Lys Gln Tyr Asn Ala     370              #    375              #    380 Pro Asn Glu His Gly Met Cys Ile Lys Pro A #sn Lys Ala Lys Thr Glu 385                  #390                  #395                  #400 Met Lys Glu Leu Arg Leu Leu Cys Ala Glu A #sp Glu Gln Ile Arg Thr                 405  #                410  #                415 Cys Trp Met Thr Ala Phe Arg Leu Leu Lys T #yr Gly Met Leu Leu Tyr             420      #            425      #            430 Gln Asn Tyr Arg Ile Pro Gln Arg Lys Gly L #eu Pro Pro Pro Phe Asn         435          #        440          #        445 Ala Pro Met Arg Ser Val Ser Glu Asn Ser L #eu Val Ala Met Asp Phe     450              #    455              #    460 Ser Gly Gln Ile Gly Arg Val Ile Asp Asn P #ro Ala Glu Ala Gln Ser 465                  #470                  #475                  #480 Ala Ala Leu Glu Glu Gly His Ala Trp Arg A #sn Gly Ser Thr Arg Met                 485  #                490  #                495 Asn Ile Leu Ser Ser Gln Ser Pro Leu His P #ro Ser Thr Leu Asn Ala             500      #            505      #            510 Val Ile His Arg Thr Gln His Trp Phe His G #ly Arg Ile Ser Arg Glu         515          #        520          #        525 Glu Ser His Arg Ile Ile Lys Gln Gln Gly L #eu Val Asp Gly Leu Phe     530              #    535              #    540 Leu Leu Arg Asp Ser Gln Ser Asn Pro Lys A #la Phe Val Leu Thr Leu 545                  #550                  #555                  #560 Cys His His Gln Lys Ile Lys Asn Phe Gln I #le Leu Pro Cys Glu Asp                 565  #                570  #                575 Asp Gly Gln Thr Phe Phe Thr Leu Asp Asp G #ly Asn Thr Lys Phe Ser             580      #            585      #            590 Asp Leu Ile Gln Leu Val Asp Phe Tyr Gln L #eu Asn Lys Gly Val Leu         595          #        600          #        605 Pro Cys Lys Leu Lys His His Cys Ile Arg V #al Ala Leu     610              #    615              #    620 <210> SEQ ID NO 5 <211> LENGTH: 339 <212> TYPE: PRT <213> ORGANISM: Caenorhabditis elegans <400> SEQUENCE: 5 Val Lys Phe Phe Val Glu Asp Gly Glu Ala L #eu Gln Leu Leu Ile Asp   1               5  #                 10  #                 15 Glu Arg Trp Thr Val Ala Asp Thr Leu Lys G #ln Leu Ala Glu Lys Asn              20      #             25      #             30 His Ile Ala Leu Met Glu Asp His Cys Ile V #al Glu Glu Tyr Pro Glu          35          #         40          #         45 Leu Tyr Ile Lys Arg Val Tyr Glu Asp His G #lu Lys Val Val Glu Asn      50              #     55              #     60 Ile Gln Met Trp Val Gln Asp Ser Pro Asn L #ys Leu Tyr Phe Met Arg  65                  # 70                  # 75                  # 80 Arg Pro Asp Lys Tyr Ala Phe Ile Ser Arg P #ro Glu Leu Tyr Leu Leu                  85  #                 90  #                 95 Thr Pro Lys Thr Ser Asp His Met Glu Ile P #ro Ser Gly Asp Gln Trp             100      #            105      #            110 Thr Ile Asp Val Lys Gln Lys Phe Val Ser G #lu Tyr Phe His Arg Glu         115          #        120          #        125 Pro Val Val Pro Pro Glu Met Glu Gly Phe L #eu Tyr Leu Lys Ser Asp     130              #    135              #    140 Gly Arg Lys Ser Trp Lys Lys His Tyr Phe V #al Leu Arg Pro Ser Gly 145                  #150                  #155                  #160 Leu Tyr Tyr Ala Pro Lys Ser Lys Lys Pro T #hr Thr Lys Asp Leu Thr                 165  #                170  #                175 Cys Leu Met Asn Leu His Ser Asn Gln Val T #yr Thr Gly Ile Gly Trp             180      #            185      #            190 Glu Lys Lys Tyr Lys Ser Pro Thr Pro Trp C #ys Ile Ser Ile Lys Leu         195          #        200          #        205 Thr Ala Leu Gln Met Lys Arg Ser Gln Phe I #le Lys Tyr Ile Cys Ala     210              #    215              #    220 Glu Asp Glu Met Thr Phe Lys Lys Trp Leu V #al Ala Leu Arg Ile Ala 225                  #230                  #235                  #240 Lys Asn Gly Ala Glu Leu Leu Glu Asn Tyr G #lu Arg Ala Cys Gln Ile                 245  #                250  #                255 Arg Arg Glu Thr Leu Gly Pro Ala Ser Ser M #et Ser Ala Ala Ser Ser             260      #            265      #            270 Ser Thr Ala Ile Ser Glu Val Pro His Ser L #eu Ser His His Gln Arg         275          #        280          #        285 Thr Pro Ser Val Ala Ser Ser Ile Gln Leu S #er Ser His Met Met Asn     290              #    295              #    300 Asn Pro Thr His Pro Leu Ser Val Asn Val A #rg Asn Gln Ser Pro Ala 305                  #310                  #315                  #320 Ser Phe Ser Val Asn Ser Cys Gln Gln Ser H #is Pro Ser Arg Thr Ser                 325  #                330  #                335 Ala Lys Leu


1. A monoclonal antibody which binds to a GDU polypeptide, the polypeptide having an amino acid sequence as shown in SEQ ID NO:2.
 2. A method of detecting the presence of GDU in a sample, the method comprising reacting the sample with a monoclonal antibody as claimed in claim 1 and detecting the binding of the antibody. 